Fix eCharts label text alignment in Firefox browser for Storybook svg rendered charts
Firefox displays misaligned text in some of our charts.
This only happens in Storybook, and not in the GitLab project (maybe this deserves an investigation why the behaviour isn't consistent).
This can be due to an eCharts bug. It's signalled in this issue: https://github.com/apache/incubator-echarts/issues/10620
(see both x-axis and y-axis labels)